1. Field of the Invention
The present invention relates to an improvement of a vehicle equipment remote control system that automatically releases a locked state of a door in response to a vehicle user carrying a portable transceiver approaching the vehicle to get into the vehicle; enables the steering to be operated by releasing a steering lock when the vehicle user carrying the portable transceiver gets into the vehicle; and automatically puts the door in a locked state in response to the vehicle user carrying the portable transceiver moving away from the vehicle.
2. Description of the Related Art
Conventionally, such a system is known in, for example, Japanese Patent Application Laid-open No. 11-336394. Furthermore, switchover intention detection means is known in, for example, Japanese Patent Application Laid-open No. 10-308149 wherein, in order to obtain a trigger signal to automatically release a locked state of a door to unlock the door, the switchover intention detection means confirms the intention of a vehicle user to switch over from the locked state to an unlocked state by, for example, detecting that the vehicle user has touched an outer handle.
In order that interference between portable transceivers may be prevented when there are a plurality of portable transceivers corresponding to the vehicle in the vicinity thereof, and in order that the doors may be prevented from being automatically locked when the vehicle user gets out of the vehicle while leaving a portable transceiver within the occupant compartment, ideally vehicle exterior transmitters positioned on left and right outer sides of an occupant compartment can only communicate with a portable transceiver that is on the left or right side of the vehicle, and a vehicle interior transmitter positioned within the occupant compartment can only communicate with a portable transceiver that is present within the occupant compartment.
Since the vehicle exterior transmitters positioned on the left and right outer sides of the occupant compartment are required to have their transmission output increased to the statutory level because of the necessity to increase the distance over which communication is possible, they can also communicate with a portable transceiver that is present within the occupant compartment. In order to carry out bidirectional communication upon identifying whether a portable transceiver is present within the occupant compartment or outside the vehicle on the left or right, communication is conventionally carried out between the portable transceiver and each of the vehicle exterior transmitters and the vehicle interior transmitter so as to identify the portable transceiver that is the target of communication.
However, if identification of a portable transceiver as the target of communication is carried out by the conventional method, communication takes comparatively long time. Therefore, the responsiveness of system operation cannot be excellent, leading to a possibility that, for example, if a vehicle user opens a door quickly to get into the vehicle, the locked state of the door may not be released in time to open the door.
The present invention has been achieved in view of the above-mentioned circumstances, and it is an object of the present invention to provide a vehicle equipment remote control system that can quickly identify the portable transceiver that is the target of communication, thereby enhancing the responsiveness of system operation.
In order to accomplish the object, in accordance with a first aspect of the present invention, there is proposed a vehicle equipment remote control system comprising: vehicle exterior transmitters disposed on at least both left and right outer sides of an occupant compartment in a vehicle; a vehicle interior transmitter disposed within the occupant compartment; a vehicle receiver disposed in the vehicle; a portable transceiver that transmits reply data in response to reception of a request signal requesting reply data from each of the transmitters; door lock means for switching over doors on both the left and right sides of the vehicle between a locked state and a unlocked state; switchover intention detection means that are mounted in the doors on the left and right sides and can detect a vehicle user""s intention to switch over the doors between the locked state and the unlocked state; and an electronic control unit mounted in the vehicle so as to control the operation of the door lock means in response to the detection output of the switchover intention detection means and the reception output of the vehicle receiver and to control the transmission from the vehicle exterior and interior transmitters; wherein, when the vehicle prompts the transmission of reply data from the portable transceiver, the electronic control unit controls the transmissions from the vehicle exterior transmitters and the vehicle interior transmitter such that, if one of the switchover intention detection means on the left and right sides detects the vehicle user""s intention to switch over the doors between the locked state and the unlocked state, the vehicle exterior transmitter on the side where the switchover intention detection means that has detected the switchover intention is located transmits a request signal requesting reply data, and at least one of the remaining vehicle exterior transmitter and the vehicle interior transmitter transmits a prohibition signal to prohibit the transmission of reply data from the portable transceiver, the prohibition signal being at a low output level that cannot be received by the portable transceiver that is present on the side where the switchover intention detection means that has detected the switchover intention is located, among the left and right sides on the outside of the vehicle.
In accordance with this arrangement, when the portable transceiver is present outside the vehicle, as a result of detection of the vehicle user""s switchover intention by the switchover intention detection means mounted in the doors on both the left and right sides of the vehicle, reply data is transmitted from the portable transceiver to the vehicle receiver in response to a request signal requesting reply data from the vehicle exterior transmitter on the side where the switchover intention detection means that has detected the switchover intention is located. At least one of a portable transceiver within the occupant compartment and a portable transceiver on the side opposite to the side where the switchover intention detection means that has detected the switchover intention is located, receives the prohibition signal and does not transmit reply data. It is therefore possible to quickly identify whether the portable transceiver is located on the left or right side of the vehicle, thereby enhancing the responsiveness of system operation. Furthermore, interference with any portable transceiver other than the identified portable transceiver can be prevented and the doors can be switched over quickly between the locked and unlocked states. Moreover, since the prohibition signal is transmitted at a low output level that cannot be received by the portable transceiver on the side where the switchover intention detection means that has detected the switchover intention is located, communication between the portable transceiver that has been identified as the target of communication and the vehicle receiver will not be impaired by the prohibition signal.
In accordance with a second aspect of the present invention, in addition to the first aspect, there is proposed a vehicle equipment remote control system wherein the electronic control unit controls the transmission of the vehicle exterior transmitters and the vehicle interior transmitter so as to transmit the prohibition signal within a predetermined period of time after transmission of the request signal is completed, and the portable transceiver transmits reply data on the condition that it has not received the prohibition signal during the predetermined period of time after receiving the request signal. In accordance with such an arrangement, since the prohibition signal does not reach the portable transceiver on the side where the switchover intention detection means that has detected the switchover intention is located, the portable transceiver transmits reply data to the vehicle receiver after the predetermined period of time following completion of reception of the request signal. The other portable transceivers receive the prohibition signal and are thereby prohibited from transmitting reply data. Therefore, identification of the portable transceiver that is the target of communication can be conducted easily.
In accordance with a third aspect of the present invention, in addition to the first or second aspect, there is proposed a vehicle equipment remote control system wherein the electronic control unit controls the transmission from the vehicle exterior transmitters and the vehicle interior transmitter by transmitting the prohibition signal during transmission of the request signal. In accordance with such an arrangement, while the portable transceiver that is present on the side where the switchover intention detection means that has detected the switchover intention is located, is receiving the request signal, the other portable transceivers receive the request signal and the prohibition signal at the same time, and since the request signal cannot be received properly, no response will be made, thereby quickly identifying the portable transceiver that is the target of communication.
The above-mentioned object, other objects, characteristics and advantages of the present invention will become apparent from an explanation of a preferred embodiment that will be described in detail below by reference to the attached drawings.